Patent•
Coaxial cable bragg grating sensor
02 Apr 2012-
TL;DR: In this article, a coaxial cable sensor device with periodic impedance discontinuities along the length of its cable is described, which can be used to measure temperature, pressure, strain, and acoustic waves in building structures.
Abstract: A coaxial cable sensor device with periodic impedance discontinuities along the length of its cable. The cable comprises an inner conductor, insulating material disposed around the length of the inner conductor, and an outer conductor disposed around the insulating material. The periodic impedance discontinuities are created by physical deformations or material alterations to at least one of the inner conductor, the outer conductor, and the insulating material. The sensor device may be used to measure temperature, pressure, strain, and acoustic waves in building structures, and is well suited for down-hole or underwater applications.
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Patent•
AT&T1
TL;DR: In this paper, the authors describe a system that receives, by a feed point of a dielectric antenna, electromagnetic waves from a core coupled to the feed point without an electrical return path, and radiates a wireless signal responsive to the electromagnetic waves being received at the aperture.
Abstract: Aspects of the subject disclosure may include, for example, receiving, by a feed point of a dielectric antenna, electromagnetic waves from a dielectric core coupled to the feed point without an electrical return path, where at least a portion of the dielectric antenna comprises a conductive surface, directing, by the feed point, the electromagnetic waves to a proximal portion of the dielectric antenna, and radiating, via an aperture of the dielectric antenna, a wireless signal responsive to the electromagnetic waves being received at the aperture. Other embodiments are disclosed.
330 citations
Patent•
AT&T1
TL;DR: In this paper, a distributed antenna and backhaul system provide network connectivity for a small cell deployment using high-bandwidth, millimeter-wave communications and existing power line infrastructure, rather than building new structures, and installing additional fiber and cable.
Abstract: A distributed antenna and backhaul system provide network connectivity for a small cell deployment. Rather than building new structures, and installing additional fiber and cable, embodiments described herein disclose using high-bandwidth, millimeter-wave communications and existing power line infrastructure. Above ground backhaul connections via power lines and line-of-sight millimeter-wave band signals as well as underground backhaul connections via buried electrical conduits can provide connectivity to the distributed base stations. An overhead millimeter-wave system can also be used to provide backhaul connectivity. Modules can be placed onto existing infrastructure, such as streetlights and utility poles, and the modules can contain base stations and antennas to transmit the millimeter-waves to and from other modules.
298 citations
Patent•
AT&T1
TL;DR: In this article, a distributed antenna system is provided that frequency shifts the output of one or more microcells to a 60 GHz or higher frequency range for transmission to a set of distributed antennas.
Abstract: A distributed antenna system is provided that frequency shifts the output of one or more microcells to a 60 GHz or higher frequency range for transmission to a set of distributed antennas. The cellular band outputs of these microcell base station devices are used to modulate a 60 GHz (or higher) carrier wave, yielding a group of subcarriers on the 60 GHz carrier wave. This group will then be transmitted in the air via analog microwave RF unit, after which it can be repeated or radiated to the surrounding area. The repeaters amplify the signal and resend it on the air again toward the next repeater. In places where a microcell is required, the 60 GHz signal is shifted in frequency back to its original frequency (e.g., the 1.9 GHz cellular band) and radiated locally to nearby mobile devices.
296 citations
Patent•
AT&T1
TL;DR: In this article, the authors describe a device that facilitates transmitting electromagnetic waves along a surface of a wire that facilitates delivery of electric energy to devices, and sensing a condition that is adverse to the electromagnetic waves propagating along the surface of the wire.
Abstract: Aspects of the subject disclosure may include, for example, a device that facilitates transmitting electromagnetic waves along a surface of a wire that facilitates delivery of electric energy to devices, and sensing a condition that is adverse to the electromagnetic waves propagating along the surface of the wire. Other embodiments are disclosed.
288 citations
Patent•
AT&T1
TL;DR: In this article, a system for detecting a fault in a first wire of a power grid that affects a transmission or reception of electromagnetic waves that transport data and that propagate along a surface of the first wire is described.
Abstract: Aspects of the subject disclosure may include, for example, a system for detecting a fault in a first wire of a power grid that affects a transmission or reception of electromagnetic waves that transport data and that propagate along a surface of the first wire, selecting a backup communication medium from one or more backup communication mediums according to one or more selection criteria, and redirecting the data to the backup communication medium to circumvent the fault. Other embodiments are disclosed.
286 citations
References
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TL;DR: In this paper, the spectral properties of fiber reflection and transmission gratings are described and examples are given to illustrate the wide variety of optical properties that are possible in fiber gratings.
Abstract: In this paper, we describe the spectral characteristics that can be achieved in fiber reflection (Bragg) and transmission gratings. Both principles for understanding and tools for designing fiber gratings are emphasized. Examples are given to illustrate the wide variety of optical properties that are possible in fiber gratings. The types of gratings considered include uniform, apodized, chirped, discrete phase-shifted, and superstructure gratings; short-period and long-period gratings; symmetric and tilted gratings; and cladding-mode and radiation-mode coupling gratings.
3,330 citations
TL;DR: In this article, the problem of propagation and interaction of optical radiation in dielectric waveguides is cast in the coupled-mode formalism, which is useful for treating problems involving energy exchange between modes.
Abstract: The problem of propagation and interaction of optical radiation in dielectric waveguides is cast in the coupled-mode formalism. This approach is useful for treating problems involving energy exchange between modes. A derivation of the general theory is followed by application to the specific cases of electrooptic modulation, photoelastic and magnetooptic modulation, and optical filtering. Also treated are nonlinear optical applications such as second-harmonic generation in thin films and phase matching.
1,952 citations
TL;DR: The importance of implementing long-term structural health monitoring systems for large-scale bridges, in order to secure structural and operational safety and issue early warnings on damage or deterioration prior to costly repair or even catastrophic collapse, has been recognized by bridge administrative authorities.
879 citations
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TL;DR: In this paper, the authors give a brief historic perspective of the coupled mode theory and the development and applications of the theory in microwaves in early years and in optoelectronics and fiber optics in recent years.
Abstract: The authors give a brief historic perspective of the coupled mode theory. The development and applications of the theory in microwaves in early years and in optoelectronics and fiber optics in recent years are described. They then consider lossless coupling of two modes in time. Two coupled resonance circuits, or two coupled microwave or optical resonators, are the physical examples. The start-up of a parametric oscillator is another example. Then they look at the formal derivation of coupled mode theory and consider the more general case when the modes are not energy-orthogonal and the energies are not necessarily positive. A more detailed account of the nonorthogonal coupled mode theory developed in the last five years for optical waveguides is given. >
853 citations
TL;DR: In this paper, the authors present an overview of current research and development in the field of structural health monitoring with civil engineering applications, including building, piles, bridges, pipelines, tunnels, and dams.
838 citations